Consolidated Statements of Changes in Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Convertible Preferred Stock
Temporary equity, Beginning Balance, Shares at Dec. 31, 2019					207,164
Temporary equity, Beginning Balance at Dec. 31, 2019					$ 129,870
Beginning Balance at Dec. 31, 2019	$ 11,267	$ 1	$ 3,304	$ (121,908)
Beginning Balance, Shares at Dec. 31, 2019		7,034
Common shares issued for acquisitions, Shares		1,000
Conversion of Compass Therapeutics LLC preferred shares into common shares upon consummation of the reverse merger		$ 3	129,867
Temporary equity, Conversion of Compass Therapeutics LLC preferred shares into common shares upon consummation of the reverse merger, Shares					(207,164)
Temporary equity, Conversion of Compass Therapeutics LLC preferred shares into common shares upon consummation of the reverse merger					$ (129,870)
Conversion of Compass Therapeutics LLC preferred shares into common shares upon consummation of the reverse merger, Shares		30,630
Common shares issued in Public Offering net of issuance costs	54,231	$ 1	54,230
Common shares issued in private placement, net of issuance costs, Shares		12,096
Stock Issued During Period Value New Issues	54,231	$ 1	54,230
Stock Issued During Period Shares New Issues		12,096
Payment to non-participating Compass Therapeutics LLC members upon consummation of Merger	(69)	$ 0	(69)
Payment to non-participating Compass Therapeutics LLC members upon consummation of Merger, Shares		(13)
Vesting of share-based awards		474
Stock-based compensation expense	4,016		4,016
Net loss	(29,500)			(29,500)
Ending Balance at Dec. 31, 2020	39,945	$ 5	191,348	(151,408)
Ending Balance, Shares at Dec. 31, 2020		51,221
Common shares issued for acquisitions	$ 50,300	$ 1	50,299	0
Common shares issued for acquisitions, Shares	10,265
Common shares issued in Public Offering net of issuance costs	$ 127,985	$ 4	127,981	0
common shares issued in public offering, net shares		38,987
Stock Issued During Period Value New Issues	127,985	$ 4	127,981	0
Vesting of share-based awards		359
Stock-based compensation expense	4,029		4,029
Net loss	(82,181)			(82,181)
Ending Balance at Dec. 31, 2021	$ 140,078	$ 10	$ 373,657	$ (233,589)
Ending Balance, Shares at Dec. 31, 2021		100,832